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Lindsey's D&D Unit 3 > Antibacterial Agents IV: DNA Function Inhibitors > Flashcards

Antibacterial Agents IV: DNA Function Inhibitors Flashcards

(69 cards)

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1
Q

What drugs interact with Metronidazole?

A

inhibitors and inducers of CYP450

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2
Q

Tx for Giardia lamblia giardiasis?

A

Metronidazole

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2
Q

Give an example of resistance due to escape.

A

Sulfonamides are noncompetitively antagonized by methionine, homocysteine, serine, purines, and thymine

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3
Q

What are the adverse rxns for Nitrofurantoin use?

A

GI upset, occasionally hypersensitivity rxns, neuropathy, birth defects

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3
Q

Tx of Pseudomonas aeruginosa burn infections?

A

topical silver sulfadiazine

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4
Q

Why are Sulfonamides selectively toxic?

A

humans don’t synthesize their own folic acid

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5
Q

Tx of Plasmodium (resistant) malaria?

A

sulfadoxine + pyrimethamime

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6
Q

How do the Sulfonamides work?

A

they’re analogs of PABA that competitively inhibit dihydropteroate synthetase (enzyme used to synthesize folic acid)

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6
Q

What drug can predispose neonates to kernicterus? Why?

A

Sulfonamides; its protein binding displaces bilirubin

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6
Q

Tx of MRSA skin infections?

A

TMP/SMX

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7
Q

Name the Abx that inhibit DNA function (4).

A
  1. fluoroquinolones (-floxacin) 2. Nitrofurantoin 3. Metronidazole 4. Sulfonamides (Sulfa-)
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7
Q

Sulfonamides have synergy with _____, which inhibits dihydrofolate reductase (DHFR).

A

trimethoprim (TMP)

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8
Q

What is the tx for Staph. aureus (MSSA) skin infections?

A

levofloxacin, moxifloxacin, gemifloxacin (respiratory quinolones)

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8
Q

Inhibitors of _____ have increased potential for human toxicity.

A

dihydrofolic acid reductase

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9
Q

Tx for Entamoeba histolytica amebiasis?

A

Metronidazole

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10
Q

Tx for C. diff diarrhea, pseudomembranous colitis?

A

Metronidazole

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10
Q

Sulfonamides have synergy with trimethoprim (TMP), which inhibits _____.

A

dihydrofolate reductase (DHFR)

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11
Q

Name the 4 fluoroquinolones.

A
  1. ciprofloxacin 2. levofloxacin 3. gemifloxacin 4. moxifloxacin
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11
Q

Name 3 methods of resistance that Sulfonamides use?

A
  1. acquired (increased PABA or altered DHPS) 2. escape (end products from pus) 3. natural (no folic acid req = not susceptible)
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12
Q

Tx for Clost. perfringens gas gangrene, food poisoning?

A

Metronidazole

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13
Q

Tx for Trichomonas vaginalis trichomoniasis?

A

Metronidazole

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15
Q

What is the mechanism of action of the fluoroquinolones?

A

inhibits DNA gyrase and topo IV

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16
Q

Tx for Helicobacter pylori gastritis, peptic ulcers?

A

Metronidazole

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16
Q

Tx of U.C.?

A

sulfasalazine

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17
Tx of Moraxella catarrhalis otitis media?
TMP/SMX
19
What are the adverse rxns for the fluoroquinolones?
GI upset, CNS issues, QT elongation, skin rashes, abn glucose, tendon rupture, arthropathies
19
What is TMX/SMX?
trimethoprim/sulfamethoxazole combo drug (sulfonamide class)
20
Tx of Norcardia nocardiosis?
sulfisoxazole, sulfadiazine
21
What is the tx for Moraxella catarrhalis sinusitis, bronchitis?
levofloxacin
21
What is the tx for Chlamydia trachoma, C.A. pneumonia, urethritis?
moxifloxacin, gemifloxacin
22
Why do antacids negatively affect fluoroquinolones?
they reduce oral absorption of cipro
23
What is the tx for Myco. pneumoniae C.A. pneumonia?
moxifloxacin, gemifloxacin
24
Why do Sulfonamides have a delayed onset of action?
the folate stores have to be depleted
25
How is Metronidazole absorbed, distributed, and metabolized?
GI not affected by food; good dist including CSF and bone; hepatic metabolism
27
What is the tx for Bacilllis anthracis anthrax?
ciprofloxacin
28
Sulfonamides are ____ spectrum Abx.
broad
30
How are fluoroquinolones absorbed, distributed, metabolized, and excreted?
A: orally or parenterally D: into most tissues, including bone, fat, muscle, prostate, repro organs, and urine M: minimal E: kidney
31
\_\_\_\_ should cease until 24-48 hours post Metronidazole therapy because \_\_\_\_\_.
Breast feeding; it can be carcinogenic
32
Is Metronidazole bactericidal or bacteriostatic?
bactericidal
33
Combination use of Sulfonamides + trimethoprim (TMP) is BACTERIOSTATIC/BACTERICIDAL.
BACTERICIDAL
34
Trimethoprim (TMP), used with sulfonamides, is also used in combination with \_\_\_\_\_.
sulfamethoxazole
36
What is Nitrofurantoin used for?
URIs
36
Are Sulfonamides bacteriostatic or bactericidal?
bacteriostatic
38
What is the tx for Strep. pneumoniae pneumonia, chronic bronchitis, acute sinusitis?
levofloxacin, moxifloxacin, gemifloxacin (respiratory quinolones)
40
Which drug is contraindicated in pregnancy and in children under 18yo?
fluoroquinolones
42
Why is Nitrofurantoin selectively toxic?
mammalian enzymes don't reduce Nitrofurantoin as rapidly
44
What are the adverse rxns for Metronidazole?
nausea, dry mouth, headache, metallic taste, candida superinfections
45
Where do bacteria obtain methionine, homocysteine, serine, purines, and thymine used to escape (resistance)?
from pus
46
How does resistance to fluoroquinolones occur, and how often?
point mutations in the binding site on DNA gyrase, or a change in drug permeability- plasma mediated; 10^7-10^9 organisms
47
What is the absorption, distribution, metabolism, and excretion of the sulfonamides?
well absorbed from the GI tract on an empty stomach but with plenty of fluids; distributed widely in body water including pleural, ocular, synovial fluid, and CSF- crosses placenta; N-acetylated to inactive compound; excreted by kidney with increasing pH and in breast milk
48
Which drugs interact with the fluoroquinolones?
theophylline (esp with ciprofloxacin), antacids (with cipro)
49
Tx of Shigella diarrhea?
TMP/SMX (preferred over quinolones in children)
51
What is the mechanism of action for Metronidazole?
transformed into a reactive nitro radical anion that breaks DNA and inhibits replication
52
What happens to the urine in Nitrofurantoin use?
it turns brown
53
Tx of Klebsiella, Proteus, Enterobacter UTIs?
TMP/SMX
54
What is the tx for Pseudomonas aeruginosa, E. coli, Klebsiella, Serratia, Proteus, Enterobacter, Shigella, Salmonella UTIs and traveler's diarrhea?
ciprofloxacin, levofloxacin
55
How does Nitrofurantoin work?
reduced by bacterial enzymes to intermediates that damage bacterial DNA
57
Is Nitrofurantoin bacteriostatic or bactericidal?
both, depending on the conc
58
What is the tx for Richettsia rocky mountain spotted fever, Q fever?
moxifloxacin, gemifloxacin
59
What are the 6 adverse rxns with Sulfonamides?
1. sensitization rxns 2. renal damage 3. hemolytic anemia in G6PD pts 4. GI upset 5. category C in pregnancy 6. drug interactions (bilirubin, oral anticoagulants, sulfonylurea hypoglycemic agents)
60
\_\_\_\_\_\_ have synergy with trimethoprim (TMP), which inhibits dihydrofolate reductase (DHFR).
Sulfonamides
61
Tx for Bacteriodes fragilis intraabd and brain abscesses?
Metronidazole
62
How is Nitrofurantoin absorbed and excreted?
complete from GI tract; into urine via filtration and excretion
64
What is the tx for H. influenzae lower RI, pneumonia?
moxifloxacin, levofloxacin
64
Tx of Staph. aureus conjunctivitis?
sulfacetamide
65
What should be avoided during Metronidazole therapy?
alcohol, pregnancy, breast-feeding
67
Tx of Chlamydia trachoma, C.A. pneumonia, urethritis?
TMP/SMX
68
Choose: Fluoroquinolones are BACTERICIDAL/BACTERIOSTATIC.
bactericidal
69
Tx of Pneumocystis carinii pneumonia?
TMP/SMX

Lindsey's D&D Unit 3 (12 decks)

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